Daylighting
- 2. INDEX:- 1.INTRODUCTION 1.1 WHAT IS DAYLIGHTING? 1.1.1 SOURCES OF DAYLIGHTING 1.2 METHODS OF DAYLIGHTING 1.3 WHY DAYLIGHTING? 1.4 ADVANTAGES AND DISADVANTAGES 2.MASSING FOR DAYLIGHTING 3.BASIC PRINCIPLES OF DAYLIGHTING 3.1 BUILDING ORIENTATION 3.2 FORM OF BUILDING 3.3 GLAZING RATIO 3.4 GLAZING SPECIFICATION 4.5 OVERHEAD DAYLIGHTING 3.5.1 SKYLIGTHS 3.5.2 CLERSTORIES 5.6 REDIRECTING LIGHT 4.COMPONENTS 5.IMPORTANCE IN SUSTAINABLE BUILDING 6.WAYS TO MAKE SUSTAINABLE DESIGN 7.TYPES OF TECHNOLOGY 8.ASSOCIATIONS AND ORGANIZATIONS 9.CONCLUSION
- 3. DAYLIGHTING IS THE PRACTICE OF PLACING WINDOWS, SKYLIGHTS, OTHER OPENINGS, AND REFLECTIVE SURFACES SO THAT SUNLIGHT(DIRECT OR INDIRECT) CAN PROVIDE EFFECTIVE INTERNAL LIGHTING. PARTICULAR ATTENTION IS GIVEN TO DAYLIGHTING WHILE DESIGNING A BUILDING WHEN THE AIM IS TO MAXIMIZE VISUAL COMFORT OR TO REDUCE ENERGY USE. ENERGY SAVINGS CAN BE ACHIEVED FROM THE REDUCED USE OF ARTIFICIAL (ELECTRIC) LIGHTING OR FROM PASSIVE SOLAR HEATING. SOURCES OF DAYLIGHTING: • The primary source of light for daylighting is the sun. • The light received by the earth from the sun consists of two parts: • Direct solar illumination • Design Methods WHY DAYLIGHING? 1.Improved aesthetics 2.Good daylighting design is beneficial to health. 3.Daylighting to humans is important in that it is necessary for visual comfort and providing psychological needs 4.Using natural light from the sun costs nothing to the environment but pays big dividends to building occupants. 5.Reduce lighting costs. The overall objective of daylighting is to minimize the amount of artificial light and reduce electricity costs.
- 4. Colour rendition Occupant Satisfaction Colour Temperature Reduced electrical load Time Orientation Increased heat gains Glare! Functional interference Increased cooling loads ADVANTAGES- DISADVANTAGE
- 5. MASSING FOR DAYLIGHTING • Massive for visual comfort. • It can be very difficult to get consistent daylight and control glare from east and west windows. • However, the side of the building facing the sun's path (the equator- facing side) can generally be easily shaded with overhangs, light shelves, or louvers, the side of the building away from the sun's gets little or no glare. • Therefore, generally buildings that are longer on their east-west axis are better for daylighting and visual comfort. USEFUL DAYLIGHT (STRAIGHT ARROWS) AND UNWANTED GLARE (JAGGED ARROWS) ON DIFFERENT FACES OF A BUILDING.
- 6. • The orientation of buildings is important, if the length of the building is oriented in an east-west axis, it will allow penetration of passive heating or cooling within the building on a seasonal basis). • A north-south facade is better as it allows penetrating a good daylight by avoiding glare and overheating. • Designers could define which rooms need direct or indirect sunlight and require the quantity of heat or heat loss. BUILDING ORIENTATION BASIC PRINCIPLES OF EFFECTIVE DAYLIGHT DESIGN-
- 7. • Orient the majority of the glazing north-south, with a maximum exposure to more easily controllable daylight. • •South, is desirable because direct solar radiation received by the south facade is easier to control to prevent excess solar gain. Daylight is relatively uniform. • •North light is the best for daylighting because it is not direct and constant diffuse skylight. It is facade is advantageous for uniform and soft daylighting. • •Toward the east and west the sun is very low—almost horizontal—so it is hard to control. Orientation 1 is worst for daylighting, 3 is good, and 2 is best. BUILDING ORIENTATION FORM OF BUILDING- Identifies the quality of daylight. Different shapes, thin linear, L shape, U-shape and doughnut need enough natural light through the courtyard and thin building Courtyard and thin building, increase the natural light and heat distribution to the sides of building.
- 8. Glazing provides natural daylight but also allows unwanted summer solar gains and winter heat losses. The larger the windows the more daylight and solar gain will enter - but the larger the heat losses will be. Recommended glazing ratios are generally between 25-50% of the external wall of the daylight space The optimum glazing ratio may vary due to individual factors such as orientation, location, obstructions (View of sky) and activity/user requirements. GLAZING RATIO- GLAZING SPECIFICATIONS- • The type of glazing has a direct influence on thermal performance and daylight levels. • Triple glazing gives greater thermal comfort because its internal temperature is closer to the internal air conditions. • Triple glazing, tinted or reflective glass can result in reduced daylight levels. WINDOW SPECIFICATION DAYLIGHT TRANSMISSIO N SOLAR TRANSMISSION SINGLE GLAZING 88% 83% DOUBLE GLAZING 77-80% 65-70% DOUBLE GLAZINGTINTED 29% 39% TRIPLE GLAZING 70% 40-60%
- 9. OVERHEAD DAY LIGHTING There are several top-lighting methods: Skylights Clerestories. SKYLIGHTS- Skylights are domed, horizontal or slightly sloping glazed openings in the roof. CLERESTORIES • Clerestory windows are usually situated at a high level (near the ceiling of the room) - always above eye level. • They provide an effective source of natural light and ventilation whilst reducing glare.
- 10. Redirecting light is the use of building elements to bounce sunlight into more desirable locations in the building. Light shelves and baffles are two strategies that can distribute light more evenly. A light shelf avoiding glare and pulling daylight deeper into the room Baffles in a roof monitor avoid direct glare while bringing in the sun's full brightness REDIRECTING LIGHT-
- 11. COMPONENTS OF DAYLIGHTING- A daylighting system consists of systems, technologies, and architecture. While not all of these components are required for every daylighting system or design, one or more of the following are typically present: Daylight-optimized building footprint Climate-responsive window-to-wall area ratio Solar shading devices High-performance glazing Daylighting- optimized fenestration design WHY DAYLIGHTING IS IMPORTANT FOR SUSTAINABLE BUILDING SOLUTIONS? • One of the largest sources of energy use in a commercial building is artificial lighting. • Better ways to save energy that still keep the quality and the productivity of the workplace at a high level. Natural daylighting is the answer. • It is an important sustainable building solution, because it effectively illuminates any area with no ongoing cost.
- 12. WAYS DAYLIGHT CAN MAKE DESIGN MORE SUSTAINABLE • Optimize urban design and building orientation. • The perfect size, form and glazing treatment for windows. • Shading for visual comfort and cooling. • Work with bright interior surfaces.
- 13. WAYS DAYLIGHT CAN MAKE DESIGN MORE SUSTAINABLE • Move task areas close to windows. • Consider daylight reflector systems. • Energize your building with solar radiation. TYPES OF TECHNOLOGY- Exterior shading and control devices Aperture location Reflectances of room surfaces Integration with electric lighting controls Glazing materials
- 14. ASSOCIATIONS AND ORGANIZATIONS • Daylight Dividends is a multi-year joint research program of the DOE and a variety of state energy agencies facilitating the widespread implementation of daylight in buildings. • Seventhwave provides information for daylighting guidance. • ENERGY STAR, first established in 1991 as a voluntary labelling program, helps both businesses and consumers reduce costs and protect the environment through energy efficient products and practices. • International Commission on Illumination (CIE) The United States National Committee CIE/(USA) is a not-for-profit organization formed in 1913 to assist the International Commission on Illumination in achieving its objectives in the fields of light and lighting. • Illuminating Engineering Society (IES) is an organization whose mission is to advance knowledge and disseminate information for the improvement of the lighted environment for the benefit of society. • Lighting Research Center (LRC) School of Architecture, Rensselaer Polytechnic Institute, is the world's largest
- 15. CONCLUSION- • In architectural design, natural daylight is a crucial component in determining sustainable building and the quality of an indoor environment. • Many significant factors determine the quality and quantity of daylight; site orientation, form of building and type, size, location of the glazing space. • The successful design of healthy building is controlling the natural lighting and distribute in spaces according to their needs. • Using appropriate glazing specification for buildings can result in reduce daylight levels and decrease in energy use for artificial lighting.